Rickards, R.B, Rigby, S and Harris, J.H
(1989)
'Graptoloid biogeography: recent progress, future hopes.'
In: McKerrow, W.S and Scotese, C.R, eds.
Palaeozoic palaeogeography and biogeography.
The Geological Society Memoir No. 12
.
The Geological Society, pp. 139-146.
ISBN 0903317494